Data Link Connector No. 3 Inspection

2004 Toyota Celica GT, StandardSECTION Data Link Connector No. 3 Inspection
WARNING: This page is about a different car, the 2003 Toyota MR2. However, it is still accessible from the selected car via links, so may be relevant.
  1. If Toyota hand-held tester or scan tool displays UNABLE TO CONNECT TO VEHICLE when hand-held tester or scan tool is connected to Data Link Connector No. 3 (DLC3), try hand-held tester or scan tool on another vehicle. If hand-held tester or scan tool operates on another vehicle, go to next step. If hand-held tester or scan tool does not operate on another vehicle, problem is probably with hand-held tester or scan tool.
  2. Check DLC3 for loose or damaged terminals. Ensure DLC3 terminals are in correct position in connector. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. For full wiring diagram of DLC3, it may be necessary to see DATA LINK CONNECTORS in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If connector and terminals are okay, go to next step. If connector or terminals are defective, repair as necessary.
  3. Check voltage and resistance between ground and specified terminal on DLC3. See DATA LINK CONNECTOR NO. 3 VOLTAGE & RESISTANCE SPECIFICATIONSΒ . See Fig 1. If voltage and resistance readings are not as specified, check wiring circuit. See SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
DATA LINK CONNECTOR NO. 3 VOLTAGE & RESISTANCE SPECIFICATIONS

Terminal No. (Circuit) Specification
4 (Chassis Ground) 1 Ohm Or Less
5 (Signal Ground) 1 Ohm Or Less
7 (BUS Communication) (1)
16 (Battery Voltage) 9-14 Volts
(1) Pulse generation should exist during information transmission from Engine Control Module (ECM).
Fig 1: Identifying Data Link Connector Terminals
G99C52821Courtesy of Β© TOYOTA, LICENSE AGREEMENT TMS1002
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.